Adaptive Backup Research Articles

A distributed adaptive protection scheme based on multi‐agent system for distribution networks in the presence of distributed generations

Distribution networks are operated in different conditions and the traditional protection systems might not be proper for all available operation conditions by using directional overcurrent relaying. Besides, the presence of distributed generations makes the protection setting and coordination more complex, and may even make it impossible to access a reliable protection system. Therefore, a fully distributed adaptive protection scheme based on the multi-agent systems is proposed to improve the reliability, selectivity and sensitivity of relays. It uses only numerical directional overcurrent relays with instantaneous characteristics as agents, so that only need to pick-up settings and react quickly. All agents dynamically update their pickup value to increase the fault detection sensitivity, and make reliable and selective on-board decisions for fault location and isolation. In addition, in order to achieve high sensitivity and mitigate miscoordination, using setting groups of relays, a novel adaptive backup protection scheme, which does not need complex computational coordination, is proposed. The proposed system is performed in the distributed manner to enhance efficiency and robustness against cyber-attacks and one-point failures. The proposed system is tested on the meshed IEEE 14-bus system and radial IEEE 13-bus system with distributed generations to evaluate its performance.

A HDFS dynamic load balancing strategy using improved niche PSO algorithm in cloud storage

A Hadoop distributed file system (HDFS) NameNode dynamic load balancing strategy (NDLBT) using improved niche particle swarm optimisation (PSO) is proposed, which is used to solve the load balancing problem of urban surveillance video big data. Firstly, the relationship between bandwidth consumption and the bit rate of video files, the size of data blocks and access hotspots of online video files are analysed. Then, adaptive backup is realised by dynamic multiple copies of heterogeneous nodes. The dynamic distribution of metadata is implemented to ensure the performance of metadata server clusters. Finally, we propose a new improved niche PSO algorithm to achieve load balancing scheduling. In the experimental scenario where high bandwidth consumption video files are used as service access hotspots, the proposed method, which can reduce the bandwidth peak value of bottleneck nodes in data node clusters by 20%, is superior to the original load balancing method in 90% scenarios.

Wide-Area Measurement-Based Adaptive Backup Protection for Shunt Compensation Environment

In this paper, the localization issue associated with distance relay protecting a transmission line with static synchronous compensator (STATCOM) is discussed. Generally, distance relay is mal-operated due to the dynamic behaviour of STATCOM during its inductive and capacitive modes of operation. Because, STATCOM operation creates the problem of correct measurement of fault distance and is responsible of under-reach and over-reach of distance relay. Furthermore, high fault resistance is also the reason of under-reach along with STATCOM operation. To overcome aforementioned challenges, an adaptive wide-area backup protection scheme (WABPS) is addressed which compares the calculated impedance and referenced impedance. Calculated impedance is the difference between impedance measured by relay and impedance contributed by fault resistance. Referenced impedance is the sum of fault impedance and impedance contributed by STATCOM. If calculated impedance is less than referenced impedance, then the relay will generate a trip signal. Proposed WABPS is inherent directional and provides information about fault detection, fault distance, and fault resistance during dynamic operation of STATCOM. The performance of the proposed WABPS is evaluated using technology of synchronize phasor measurement and communication channel. A 230 kV, 50 Hz system with a 24-pulse STATCOM is simulated and validated using PSCAD/EMTDC software package.

Redesigning Today's Driving Automation Toward Adaptive Backup Control With Context-Based and Invisible Interfaces.

ObjectiveWe investigated a driver monitoring system (DMS) designed to adaptively back up distracted drivers with automated driving.BackgroundHumans are likely inadequate for supervising today’s on-road driving automation. Conversely, backup concepts can use eye-tracker DMS to retain the human as the primary driver and use computerized control only if needed. A distraction DMS where perceived false alarms are minimized and the status of the backup is unannounced might reduce problems of distrust and overreliance, respectively. Experimental research is needed to assess the viability of such designs.MethodsIn a driving simulator, 91 participants either supervised driving automation (auto-hand-on-wheel vs. auto-hands-off-wheel), drove with different forms of DMS-induced backup control (eyes-only-backup vs. eyes-plus-context-backup; visible-backup vs. invisible-backup), or drove without any automation. All participants performed a visual N-back task throughout.ResultsSupervised driving automation increased visual distraction and hazard non-responses compared to backup and conventional driving. Auto-hand-on-wheel improved response generation compared to auto-hands-off-wheel. Across entire driving trials, the backup improved lateral performance compared to conventional driving. Without negatively impacting safety, the eyes-plus-context-backup DMS reduced unnecessary automated control compared to the eyes-only-backup DMS conditions. Eyes-only-backup produced low satisfaction ratings, whereas eyes-plus-context-backup satisfaction was on par with automated driving. There were no appreciable negative consequences attributable to the invisible-backup driving automation.ConclusionsWe have demonstrated preliminary feasibility of DMS designs that incorporate driving context information for distraction assessment and suppress their status indication.ApplicationAn appropriately designed DMS can enable benefits for automated driving as a backup.

A New Adaptive Backup Protection Scheme Based on Intelligent Electronic Devices

A new adaptive interphase backup protection scheme based on intelligent electronic devices (IEDs) is proposed in this paper. When the system is in normal operation state, the backup protection areas are divided according to the operation status and topology of the primary and secondary devices in the power grid. When fault is detected in the system, each IED will search for the other IEDs in the same protection area and exchange the voltage and current synchronized phasor information with them. On this basis, the adaptive action factor is constructed according to the proportional relationship between the phase voltage difference and phase current after the fault. Then, by comparing and analyzing different characteristics of the adaptive action factor in normal operation state and in fault state, the adaptive interphase backup protection can be realized. Simulation results verify that the proposed method is able to identify the fault fast and accurately. It is highly sensitive to different types of interphase faults and could operate reliably even when the fault location, system structure, or system operation mode changes.

Synchronised data‐based adaptive backup protection for series compensated line

Metal oxide varistor (MOV) protected series capacitor, when present in a fault loop, modulates the impedance seen by the relay. With series capacitor placed away from the relay, the information on the level of compensation is required for proper protection decision by distance relay. In this study, synchronised data obtained at both ends are applied to calculate the compensation level which is used to adapt the relay setting for backup protection of adjacent line. The mutual coupling in the compensation portion is also considered in the apparent impedance computation. The status of capacitor during fault (bypassed or not) is obtained through impedance calculation during fault and the relay setting is adapted accordingly. Using data simulated through EMTDC/PSCAD for a series compensated line the technique is tested and found to be accurate.

Design and Test of Discrete Time Adaptive Backup Flight Control Laws

This paper is the result of a Master Thesis project performed at Saab AB. The main goal of the project was to design and implement a discrete time £1 adaptive back-up controller in pitch to increase performance for an agile fighter aircraft. A lateral controller was also developed as a secondary goal.A discrete time version of the Modified Piecewise Constant £1 adaptive control formulation was implemented. Results have shown that augmenting a state-feedback controller with an £1 adaptive controller increases robustness in the whole flying envelope, with satisfactory flying qualities. A switching scheme between two £1 controllers based on the extension of the landing gear was used to improve the controller performance throughout the whole envelope. The implemented controllers were flown in a simulator with a nonlinear generic fighter aircraft model with promising results.

Fault Factor Analysis in Complicated Electrical Engineering

Wide area adaptive backup protection is one of the research hotspots in complicated electric power system field. The researches in this paper are mainly serving wide area protection system. We will study a novel fault factor analysis in complicated electric power system, and this scheme can reduce the influence of relay protection’s wrong action device on fault detection. It has been proved by a large number of simulation experiments, even if there is the influence of random disturbance, the system failure in electric power system can be rapidly and effectively analysed by utilizing a fault factor analysis scheme. DOI: http://dx.doi.org/10.5755/j01.eee.19.10.2909

A New Approach to Fault Location in the Random Disturbance of Wind Power

The development and utilization of renewable energy resources is the future development direction. Wide area backup protection needs to locate fault element and fault section before backup protection action, and prepare for modifying fixed value of backup protection. The researches in this paper are mainly serving wide area adaptive backup protection system. Considering the development of new energy resources power system, especially the random disturbances of wind power, based on Bayes posterior decision principle, we will explore a new fault location technology. According to different types of faults, extensive simulation experiments have amply demonstrated the reliability of this fault location technology

A mixed connection recovery strategy for surviving dual link failure in WDM networks

As the size and complexity of a network increases, the probability of a dual link failure also increases. For recovering the dual link failures, two strategies have been presented in past. As per the first strategy, SPP-MAS (Shared Path Protection-Maximum Allowable Sharing), the sharing of backup lightpaths in SPP (Shared Path Protection) has been reduced, and in the second strategy TBPS (Two Backup Path Shared), the reservation of two backup lightpaths for each primary lightpath has been undertaken. The main flaw of these strategies is the requirement of redundant network resources towards the establishment of backup lightpaths, and the occurrence of trap problem after the second link fails. To minimize the redundant backup resources and the trap problem, a mixed connection recovery algorithm namely Adaptive Backup Routing over Reserved Resources (ABRRR) has been proposed. The design of ABRRR takes leverage of both, the pre-planned, and the post-failure connection recovery mechanisms. In ABRRR, the failed connections are re-provisioned adaptively over the pre-allocated backup network resources. Adaptive re-provisioning of the failed connection minimizes the trap problem. Using simulation experiments, we undertake a comparative study of the proposed strategy with the existing strategies (i.e. SPP-MAS and TBPS) under the network parameters of Blocking Probability, Dual Restorability, and Resource Utilization Ratio (RUR). Detailed investigations establish that the use of ABRRR leads to lower Blocking Probability, higher Dual Restorability, and minimized RUR compared to the existing strategies. Results also show that the proposed strategy not only survives more connections but also utilizes fewer numbers of resources compared to the existing strategies.

New Fault Discrimination under the Influence of Rayleigh Noise

The researches in this paper mainly provide service for wide area adaptive backup protection. A new fault discriminant technology based on the criterion for fault category and non-faul ...

An Effective Fault Identification Technique for Electrical Engineering

Wide area adaptive backup protection needs to locate fault element and fault section before backup protection action, and prepare for modifying fixed value of backup protection. The fault localization that works for wide area adaptive backup protection is the precondition of adaptive backup protection. Recently, numerous experts and scholars have done extensive studies on power grid alarm processing and fault diagnosis, however all of these methods utilized action information from protection or circuit breaker that is fulfilled after protection action. In this paper, according to different kinds of failures, we will study an effective fault identification technique for electrical engineering. Ill. 1, bibl. 14, tabl. 1 (in English; abstracts in English and Lithuanian).DOI: http://dx.doi.org/10.5755/j01.eee.123.7.2370

A Novel Fault Identification Using WAMS/PMU

The important premise of the novel adaptive backup protection based on wide area information is to identify the fault in a real-time and on-line way. In this paper, the principal compo ...

Abundant Indispensable Redundancies in Cellular Metabolic Networks

Cellular life is a highly redundant complex system; yet, the evolutionary maintenance of the redundancy remains unexplained. Using a systems biology approach, we infer that 37–47% of metabolic reactions in Escherichia coli and yeast can be individually removed without blocking the production of any biomass component under any nutritional condition. However, the majority of these redundant reactions are preserved because they have differential maximal efficiencies at different conditions or their loss causes an immediate fitness reduction that can only be regained via mutation, drift, and selection in evolution. The remaining redundancies are attributable to pleiotropic effects or recent horizontal gene transfers. We find that E. coli and yeast exhibit opposite relationships between the functional importance and redundancy level of a reaction, which is inconsistent with the conjecture that redundancies are preserved as an adaptation to back up important parts in the system. Interestingly, the opposite relationships can both be recapitulated by a simple model in which the natural environments of the organisms change frequently. Thus, adaptive backup is neither necessary nor sufficient to explain the high redundancy of cellular metabolic networks. Taken together, our results strongly suggest that redundant reactions are not kept as backups and that the genetic robustness of metabolic networks is an evolutionary by-product.

Adaptive backup routing for ad-hoc networks

The network topology changes frequently in ad-hoc networks. Some on-demand protocols with multi-paths or backup routes have been proposed to improve the performance in ad-hoc networks. AODV-BR scheme improves AODV routing protocols by constructing a mesh structure and providing multiple alternate routes. The algorithm establishes the mesh and multi-path using the RREP of AODV, which does not transmit many control messages. In this paper, we propose two schemes: AODV-ABR and AODV-ABL to increase the adaptation of routing protocols to topology changes by modifying AODV-BR. In AODV-ABR, the alternative route can be created by overhearing not only RREP packets but also data packets. AODV-ABL combines the benefits of AODV-ABR and Local repair. Finally, we evaluate the performance improvement by simulations.

Adaptive mechanical backup ventilation for preterm infants on respiratory assist modes – a pilot study

Mechanical respiratory-assist modes, such as assist/control, low-rate intermittent mandatory ventilation, continuous positive airway pressure, or proportional assist ventilation (PAV), require a continuous respiratory effort. Because of the frequent occurrence of periodic breathing and/or apnea, mechanical backup ventilation must be initiated during episodes of reduced or absent respiratory drive to maintain gas exchange. The common approach to this problem is a regular conventional mechanical ventilation, which is initiated and withdrawn in an "on/off" function. To develop and evaluate a mechanical backup ventilation mode that is adaptive to the rapidly changing breathing pattern of preterm infants. Prospective randomized clinical crossover trial. Neonatal intensive care unit at the University of Munich, Germany. Preterm infants undergoing PAV. The infants were ventilated with PAV using a newly developed adaptive backup support, with and without pulse-oximetry-guided operation (SpO(2)-sensitive backup). Each infant was ventilated with both modes of backup support on 2 consecutive days, with the sequence randomized. The analysis on 11 preterm infants showed a statistically significant and clinically relevant reduction of the incidence (33%) and duration of oxygen desaturations (52%) when SpO(2)-sensitive adaptive backup support was used. SpO(2)-sensitive adaptive backup proved safe and effective in reducing the incidence and duration of oxygen desaturation in this short-term trial. This technology is potentially applicable to other assisted modalities of ventilation, such as noninvasive nasal ventilation.